townsend



H. E. TOWNSEND AUTOMATIC SEAUNG MACHINE.

APPLICATION FILED IAN.10. m1

Patented Jan. 10, 192..

ATTORNEYS H. E. 1OWNSEND.

AUTOMATIC smma MACHENE.

APPLICATION HLED JAN. HMIQIT- 1 4 O2,809 Patented Jan. 10, 1922.

6 SHEEYS -SHEE" If.

/ INVENTOR H. E. TOWNSEND.

Auwmnc SEALING MACHINE.

APPLICATION HLED MN. I0, 191?.

1,402,809. 12mm. Jan. 10, 1922.

6 SHEETS SHEEI 4.

gawkwav ILIVFNTOR QA M V f ATTORNEYS APPLILAYION FILED MN, I0, 19!].

Patented Jan. 10, 1922.

6 SHEETSSHEET 6.

ATTORNEYS UNITED STATES HARRY E. TOWNSEND,

PATENT OFFICE.

OF BROOKLYN, NEW YORK, ASSIGN'OR TO THE ANCHOR CA1 15 CLOSURE CORPORATION, OF BROOKLYN, NEW YORK, A CORPORATION 01 NEW YORK.

no'rom'rxo snnnme moms.

mosses.

Specification n Letters Potent.

Patented Jan. 10, 1922.

Application filed January 10, 1917. Serial No. 141,549.

To all whom it may concern:

Be it known that I Helm! E. TowNsnNn, n citizen of the United States, and a resident of the city of Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Automatic Sealing Machines, of which the following is e specification.

This invention relates broadly to senling machines and more particularly to scaling" mnchines wherein the package is sealed in a vacuum.

The principal object of the present invention is to provide a mechunism for sealing wherein the operating cle of the machine is controlled pnelunatica ly, and particularly by the vacuum within the sealin Another object of the present invention is to provide on automatically operatin mirchinc wherein the mechanism is manna y released and after u predetermined critical vacuum is formed in the sealing chamber the opcratnig cycles of the machine are entirely automatic.

.J'i further object of the present invention is n sealing machine wherein the oiereting cycles of the machine are not started until a predetermined vacuum has been established in the sealing chamber and after cycle is started the continuation thereof is automatic until the cycle is completed.

i still further and primary object of the present invention is to provide a sealing chumher constructed to he quickly and os1- tively closed. and opened by a door wiich moves bodily toward and sway from said sealing chamber and wherein the movement or" the door adjacent the-sealing chamber is sulstnrtiully e rectilinear movement.

a l st ll further and also primal object f the present invention is to provire a substuntiully continuous sealing anvil to sustain smiling forces transmitted through the senlinn chuck. p

A still further object of the present in; rent-ion is to provide it sea-ling nnvil construrted to transmit sea-ling forces directly to the umchinc frame whereby the glass miner substantially relieved from susdirect sealing forces,

and further objects of the present ilifPllilUH will in part be obvious and will in sort he pointed out hereinafter in the specification by reference to the accompanyin drawings forming :1 part thereof, and

con roiiu ther chamber.

wherein like characters are used to represent 111cc parts throughout the several figures thereof.

Figure 1 is eview showing the machine in s1de elevation with the door open.

Figure 2 is a view showing the rear of the machine in elevation.

Figure 3 is a detail view illustrating. part of the mechanism for closing the door to the vacuum chamber.

Figure 4 is e detaili View illustrating of the mechanism for trol valve.

Figure 5 is a sectional view through the air valve.

Figure 6 is a. detail view illustratin the power mechanism operating the air vu. ve. Flgure 7 is a sectional view of the cushion- 111 device for the door when opened.

Figure 8 is a detail view showing the vecum chamber with the door open.

Figure 9 illustrates the vacuum controlled mechanism for-operating the clutch.

Figure vl0 illustrates the relationship of ports when the clutch operating mechanism ms been released.

Figure 11 is a. detail view showing the relatlonship of parts of the clutch when the control mechanism is in the position shown in Figure 9.

Figure 12 illustrates the relation of the ports of the clutch mechanism when the partsoare positioned as illustrated in Figure 1 Figures 13 and 14 illustrate further positions of the controlling mechanism showing the position thereof wherein the main exhaust line is closedand the sealing or vacuum chamber is vented to the atmosp ere.

Figure 15 is a detail view illustrating the mechanism for raisi the package to bring the cop within the e ective zone of operation of the sealing mechanism.

Figure 16 illustrates the mechanism for operating the sealing envils, and showing the smile in 0 Jon position.

Figure 17 ill ustretes the sealing envils as in closed position and adapted to sustain sealing pressure from the sealing chuck.

Figure 18 ise detail view illustrating the sealing operation.

Figure 19 is a. detail sectional view taken on the horizontal plane through substantially the mid portion of the sealing chamber.

Figure 20 illustrates the relation of parts of the sealing mechanism at the beginning of the sealing operation.

Figure 21 illustrates the relation of the sealing mechanism at the end of the sealing operation.

Heretofore in the art of vacuum sealing machines it has been customary to construct the mechanism so that the vacuum was either controlled manually or was controlled mechanically by the cycles of operation of the machine. In the manually controlled devices it frequently happened that su'flicient time was not permitted to elapse between the commencement of the air exhausting operation to form the vacuum and the sealing operation, '50 that where the sealing chucks were released too soon the sealing-cap would be blown oil by the air within the package, or too quick an operation resulted in an entirely ineflicient vacuum being formed. In the machine controlled devices there is a possibility of the operation of the machine eing speeded up so that sufiicient time is not permitted for the exluiustion of the air and consequently the goods would be sealed under an inefiicient vacuum. Furthermore, in machines of the type previously referred to no warning or provision is made against loss of vacuum by leakage, other-than in some cases fitting machines with pressure gauges, so that scoreless operator might not observe theguu'gc and would continue secling goods where the leakage was sogreat as to substantial? prevent the formation of proper and 'su cient vacuums in the scaling chamber.

The resent invention obviates the foregoing difliculties by providing a construction wherein the operating cycles of the machine, after a predetermined manual operation is performedfn're controlled by the vacuum established in the s'eulin chamber. This may be eflccted by providing a construction wherein the cycle of operation is not commenced until the formation of n predetermined vacuum which establishes an operntive con'nectionbetween a suitable source of power and the operating elements for performing the seal. By this construction it will be seen that no operation is performed until a critical vacuum has been obtnincd in the sealing chember,-by which I mean a reduction or exhaustion of gases from the chamber to the point where suitable and predetermined rarefuction has been obtained. This substantially insures that the goods are at all times sealed under the desired predetermined condition as to the vacuum.

Referring now to the drawings, and more particularly to Figures 1, 2, 3 and i, it will be noted that the control trcadle l is fixedly secured to a shaft 2 mounted in bearings 4 formed in the base of the machine frame A link, comprising sections 6 and T, is c011 bearings in the machine frnme 5.

nected at one end with the control trcadle l and at the other end with a lever S fixedly mounted on the door lifting arm shaft 9 which is likewise mounted upon suitable The tion 6 of the control link carries a spring pocket 10 which is adapted to receive and guide the lower end of the section 7. and which lower end curries a coiled spring ll that is adapted to be compressed hctwccu the collar 12 on the section 7 and the end of the spring pocket 10 when tension on the control link is greater than the strength of the coiled spring 11. The door lilting urm shaft 9 carries a pair of door supporting arms it between which the door 15 is supported by the door trunuious 16 resting in the guides 17 formed on the outer end of the door supporting arms 1-4. A )air of spring pressed plunger-s 18 norms y retain the trunnions 16 in the bottom of the guides 17. as shown in Figure 1. These spring prcsscd pliuigers act at substantially right angles to the face of the door when a door is posi tioned before the vacuum chamber (Figure ll) and are slightl compressed when the chamber is closed and the vacuum formed therein, so that when the vacuum is rob-used the plungers assist in breaking the soul between the door 15 and the walls of the chamber. It will be noted thut the face of the door is inclined upwardly and that (he door is )rovided with a suitable recess to fit the package (Figures 1, 3, 8, 15 and [9). This inclination of the door face is of great importance since it enables the door to quickly separate from the face of the chumbcr wall and automatically drop away from the sent on the scaling chamber when the \ncuum in the scaliim chamber is broken us will be hereinafter explained. A guide link 19 may be provided to assist in preventingoscillation of the door duringopening and closing movements.

Since the door 15 is relatively heavy and mounted on the outer ends of the arms ll the weight of the door drops away from the face of the vacuum chamber with consideruble force and a check is provided to receive the shock from such opening movement.

This check, as illustrated in Figures I. 2, 3 and 7, comprises a pair of: telescoping members 20 and 21 that are provided with suitable air vents, us at 22 and '-l. and a valve, as at 25, whereby air is admitted with in the member 20 when the parts are on tended and is trapped therein when [Funn-is are contracted, with the exception of lilik through the vent 22 which is :ulinshddr controlled through means of the nrcdhvcl u 26, so that this device comprises purumotic cushion against which the door is n turned by gravity when the vacuum is brol'cn.

The shaft 2 currylng (he (Onl'i'nl trcadh Hill lliil 1 also carries a'lever erm 27which is connected by means of the slotted link rod 28 with a three-arm bell-crank lever 29. This bell-crank lever 29 is mountedto rotate upon the door lifting arm-shaft 9 and. includes an arm 30 whichis connected'by-meens o'f'alink 31 with a rotary valve 32 in the air eithaust line 3-3: which line is connected with av-suitable exhaust or vacuum pump (not shown). The rotor valve 32 is normally set in closed position zFig'ure 5) when the machine is not in oaeration. The exhaust line 34 is operative connected with the sealingchamher 35, (*ifuies 8, 14; 15 and 19). The front face 0 the sealing chamber is inclined downwardly and is provided with a suitable air-tight packing joint to (ac-operate with the door 15. After the treadle 1 has been actuated to close the door 15 further pressure on the treadle compresses the spring 11 in the control lever. draws the in in the lever 27 to the bottom of the slot in the link 28, and operates the connectiousto open the exhaust line valve 32. A short cylinder 36 (Figures "1, 8, 9, 10, 1B and 14) is connected in the exhaust air line 3e between the rotary valve 32 and the sealing chamber 35. A piston 37 is mounted to reciprocate within this cylinder and is secured to a short piston rod 38. The piston 37 is of n sufficient length and is so positioned tlnit. it nets as a piston valve to cutoff or close the air exhaust line 34 when the piston is in the position shown in Figure 14. The forward end of the cylinder 36 is vented to theatmosphcre, as at 39, and the air exhaust line 34 is bynssed, as at 40, to the conduit leading to t e sealing chamber, so that whenthe piston 37 closes the exhaust line it simultaneously .or immediately thereafter rents the sealing chamber to the atmosphere. An adjustable spring 41 is provided to assist in regulating the notion of the piston to limit its movement to predetermined conditions. The forward end of the piston rod 38 is connected by means of the link 2 with a clutch control lever 44 which'is pivoted, as at 46, to the main frame and carries a roller 46 adopted to co-operate' with a rotary cam 4-7. The clutchcontrol lever is provided on its inner end with a do face 4:8 which is constructed to noru'nill lie withinthe groove 49' of the driven member 50 carried by the main shaft 51.

\ the piston rearwardly, thus withdrawing .the dog lSnnd releasing the plunger 54.

- the power shaft'fiS which carriest 1e reducing gear 59 and the belt fly wheel 60. As soon as the clutch lunger fi iengeges the pin 56 themnin 8 hit 51 commences rotation. the cam 47 operates first onroller 125 to close. the air valve 32, thus conserving the energy necessary to produce the re uired vacuum, then on roller 46 to' close ex must conduit 34 and then to vent the chamber. Meanwhile the lifter or com 61 (Figure 15) glperata'ng upon the roller 62 carried by e triangular lever 64 pivoted on the main frame, as at 65, thrusts upon the linlr G6 which is connected to the arm 67 on the lifter shaft 68 that carries the forward lifter arm 69 and lifts the forward end of this arm. This lifter arm is bifurcated at the front end to engage the lifter stand between the collars 70 and 71. A strong coiled spring 72 connected to the forward lifter arm 69 retains the roller 62 in ro c1 contact with the lifter cam 61 and iilso serves to assist in lowering the lifter stand. The lifter stand comprises a tubular incinher 74 which is screw threaded at its upper end to receive and permit the adjustment of thelifter or table rod 75 which is locked previously stated, rests against the biurouted end of the lifter arm 69 and is free to slide u on the tubular member 74. The

table rod 5 extends-into the sealing chamber 35 end is preferably packed with a. suitable gasket, as at 79.

The upper end of the table rod is recessed end'is ads. ted to receive the carrying; pin of a pee (age supporting table Si.

.he pin 80 is not locked within the table rod so that various types of tables mnv he used in accordance with the character of the package being sealed. The table herein shown comprises a substantially fint disk provided on the rear portion with a pair 0* guide pins 82 adapted to contact with the sides of a predetermined package to osition the pacmge on the table, and "the (2 mmber is also provided with the guide bill 84 which pre ents rotation of the table upon the carrying pin 80.

Immediately after the foregoing mew tinned parts have operated to lift the tnoi and connected Jar-ts, the side cums (Figures 16 and 17 operating upon the rollers 86 move the lever arms 87 which are pivoted upon brackets 88 in such manner as to separate the rollers and bring the outer ends of the lever arms nearer together against the action of the springs 89. The outer ends of the lever arms 87 are bifurcated to enclose flanged weer collars 90 that are carried by the short shafts 91 which are fixedly connected to the bend forming anvil jaws- 92. These anvil jaws 92 are mounted for reci rocntion within the upper part of the sen ing chamber 35 and are guided by a shelf 94 (Figure 17 formed in the upper part ofthe sealing chamber and by a guide bar 95 (Figures 15, 16 and 17) which is removably mounted in the u icr portion of the seulin chamber 35. his guide bar is ositione by and may also be adjusted by tne stub bolts 96. (Figures 16 and 17.)

When the bend forming anvil jaws are closed, as shown in Figure 17, the SGlLllllf' com 97 becomes active to lift the second class lever 98 which carries the anti-friction roller 99 and is suitably pivoted to the \IL- chine frame, as at 100. The s ring 101 normally maintains the roller 99 ill contact with the scaling cum 97 and maintains the parts under proper tension. The outer end of the lever 98 carries an adjustable spring connector which transmits power to the sculing lever 102. This spring connector is adjustnblc to transmit proper sealing pressure and comprises n threaded rod 104 curry innthe spring 105 which rests against the collars 106 that are loosely mounted on the threaded red 10 1. The lower collar is sustuined upon 0. pair of adjusting lock nuts 10'? and the upper collar rests directly against the end of the sealing lever 102, while the upper end of the threaded rod 104 carries a second pair of adjusting lock nuts 108. The sealing lever 102 is pivoted, as at 109, in theentreme upper ortion of the main frame and is connectc through the link 110 with the chuck carrying )lnn er 111 which enters the scaling cium icr through a suitable gland or packing 11:2. This chuck carrying longer is threaded to receive the forming cinch 11 1 and also con ries o, gravity operated pin 115 which rests upon the closure cup 116 prior to the sealing operation and during the time while the air is being exhausted from the scaling chamber 35 and from the puckuge 117, in order to prevent the scaling cap from being entirely displaced from position over the neck of the container.

As the sealing chuck descends (Figures 20 and 21) the bead 118 on the forming chuck enfimges the upper edge of the closure cap an forces this edge of the closure cup into the forming ring 119 of the anvil jaws 9'3,

thereby compressing the edge of the ('lOSULU cup and distorting the some to form the sealing bend 120 whi h forces the guskci 121 tightly uguinst the wulls oi the container 117, thus forming a completed package.

in the operation of the machine after :i suitable package, as for example (he one designated by the numeral 11'? with the closnre cup loosely seutcd on the month thereof, is set on the table 81 the o icrntor depresses the trcndle l which throng i the connecting;- links raises the door 15 in front of the scoh ing' chamber 35, as shown in Figure 15. Further pressure upon the trcndle 1 comprcsscs the spring 11. draws the pivot on th end of the lever 2? to the bottom of the slut in the link 2h, thereby operatingthe rm 3" through connected parts to rotate the valve 32. When this vnlve is opened the exhaust or vacuum maintained within. the uii"c.\'- haust line 34 becomes effective to exhaust the air from the sealingclnnnhcr 15 and also to draw the door 15 tightly against the in clined face of the sealing chamber 235. thus slightly compressing the springs in the spring plungers 18. When n predetermined vacuum has been attained in that portion of the conduit beyond the valve 32 and in cluding the scaling chamber 35, the air prcssure noting upon the forward port of tho piston 37 drives this piston inwardly :ind rcmoves the dog 18 from en agement with the clutch plunger 54. As soon us the cluhh plunger 5; is released the spring drives this plunger forward into the path of the pin or projection 56 on the continuously rotating; drive gear 55 whereby the inuin shaft :31 is now positively rotated. The rotation ot' the main shaft causes {1 cam 61. operatin through connected parts. to lift the tuhh ro 75 and raise the package so that the closure cup is in the zone of effective operations o the scaling mechanism. The cums H5 urn now effective, through councrtcd ports. to close the bead forming anvil jcws 119 so ihnt the sealing cup is snbstnntinlly cnr-ompusswl by these jaws. The scaling cum 9?. through the spring connector and rte-operating cicments, imports movement nnd PlkrSlll'l to the senling chin-l; 111. which through (-0- opcrutiou with the anvil distorts the edge o the sealing cap to form :1 head whereby :1 suitable seal is effected. The turning oi '[lio main shaft 51 brings the cum -37 into openticn on the roller 125 of the arm [2d which is fixedly connected with tho. :uin 2X on trolling the air valve 32. thereby positively closing the air vclvc. 'lllcn cum 4? non ninll comes into operation on ro ler is in drive rcurwurdly the piston i? against ilninilucucc oi: spring 11. to ricer iho or hnuw conduit 3 1 nod then to vent the scaling chamber to atmosphere. (Hon Figures 1:; und 14.) As soon :IS the vacuum in the chamber 115 is destroyed the door 1? drops IIU HIU

forming n complete 0 cumi at sealing chuc r,

directlynwuy from the contacting well of the chamber 35'to its lowered position as shown in Figure-l. The piston .37 is arranged so that under certain conditions it may act as a valveto close the exhaust conduit 34 independently of can) 47. Normally, when'the piston 37- is moved ree-rwardly by? airpressure, its movement is nrreste'd by the springel' in the position illustrated in-Figure 10, leaving 1; e exheust conduit tit-st ll in coxmuhnicationwith the sealing-chamber.

" This permits a constant vacuum being drawn on the sealing chamber during the seelin operation; -In the event of'some ebnorma operation, however, such as. too sudden or excessive drawing of the"vacuum, the air pressuremez be rendered effective to move the piston 31 to nposition to close the conduit 34, as illustrated in Figure 14, depend ing, of course, upon the adjustment of. spring 41. Upon further rotation ofshaft 51, cam t7, advancing from its ectionon the roller-d6, permit lever l i-to resume its normul position, in which dog48 is moved into. groove 49' wherein itis effective to cause withdrawal of the spring Jressed plunger 54 from engagement with t e projection or pin 56 on the drive Wheel 55, thus completing one cycle of: operations of the machine.

Realizing that my invention may he carried out by embodiments other than the specific-structure herein disclosed, I desire that such disclosure is to be understood usillustretive and not to be taken in the limiting sense.

I'l'avingthus described my invention what I claim is:

1. A sealing mechanism comprising, in mmbinution, a power shaft, :1 double noting cum mounted upon said plower shaft, 9. pair of arms cooperating wit said com, a pair of segmental zinvils operetively connecte with said arms whereby the rotation of said cum acting through said power shaft operates said arms to closescid segments thereby rative anvil, another devices operntively ronucrting said last mentioned cum with said sealing: chuck, said devices including an adjustable resilient connection whereby forces of a predetermined magnitude may be transmitted from the said last mentioned cum to the said sealing chuck, said ca-ms bein timed so that the sealin chuck becomes operative after the anvil segments have been moved to form substantially a, complete anvil.

2. In a sealing machine, the combination of a sealing chamber having a front opening therein, suitable packing material surrounding said opening and constructed to co-operube in forming an air-tight joint, a door adapted to co-opernte with said packing and close said opening, the walls of said opening open, ata'blel' within said seelin and thefeceof said door being constructed in such manner that the center .of-mess of the door is beneath the said Walls whereby the said; door 'wi1l"dr0p away by gravity from the said wells when the vacuum in said chamber is released, and. for gleam sa d door in its movement to-end from sci opening. 1 V

' .3."Ii1, a 'seelin '1' machine, in combination,

nseeling .chamjer having the front-side "i5 chamber adapted to support a suitable pac page to-be sealed; a'door for said sealing chamber, said door being provided with nninel'ined face constructed to co-operate with the sealing chamber and having :1. vertical recess-adept ed toeceommodete a package within said seahngchamber, and means for operating said door. I 8 4. In a seelinguna-chine; a chzunber 'hev' mg an 0 on front. side provided with adownwar 1y inclined. wall adjacent the mouth thereof, a door having-en upwardl i inclined face constructed to co-operate with said downwardly inclined wall, and means to guide said door to end from said inclined wall to close and open said chamber, said means being constructed to guide said door in substantially a vertical direction during the opening and closing movements.

5. In a sealing machine, in combination, a pacl'rcge sealing chamber having the open front side thereof providedwith edownwnrdly inclined wall,'a*(1oor ndapted to 'fit over said downwardly inclined wall to close said chamber, means to move said door upward-1y to close sziid chamber. means operative to cause said door to be retained in position over said chamber while thesenling operation is taking place. devices for causing said door to be released when the sealing operations are finished and to permit snid door to drop to inoperative position under the influence of gravity.

6. In a. sealing machine, the combination of n package receiving chamber having one side thereof open, the wells bounding said open side forming an inclined sealing sin. face, a door adapted to be raised up beneath and to engage said surface to close said chamber, means For causing; said door to be retained against said walls during a. predetermined cycle of operations of the machine, means for causing said door to he released. and devices to guide su-id door in its opening and closing movements whereby upon being relensed the said door will drop to open position under the influence of gravity.

7. In an automatic sealing machine, the combination of a continuously rotating drive shaft, a sealing chamber. sealing devices opcrating within said sealing chamber, a. conduit in which at suitable vacuum is maintnined, said conduit lending to said. scaling chamber, a cylinder operatively connected with said conduit, a piston constructed to reciprocate within said cylinder, a clutch connected with said piston and adapted to be released by the operation of said piston whereby said continuously rotating shaft is operatively connected with the sealing mechanism to effect a suitable seal, means for moving said piston to close the said conduit, and means whereby said vacuum chamher is vented to atmosphere after said conduit has been closed;

8. In a sealing machine, in combination, a sealing chamber, means for supporting a package in the chamber, means for exhausting the chamber, a. door separate from the chamber for closing the same, a pivoted arm carrying the door, means for actuating the arm to move the door, to the'chaniber, and a connection between the arm and the door.

whereby the latter has movement relative to the chamber independently of-the arm.

9. In a sealing machine, in'c'ombination, a sealing chamber, a. movable door forming a closure therefore, means for exhausting the chamber, a supportoperable to move the door to and from the chamber, and a connection between said support and said door whereby the latter has movement relative to the chamber independently of the support.

10. In a vacuum sealing machine, in combination, a chamber, sealing mechanism for sealing a package therein, a motive source for actuating said sealin 'mechanism, a clutch for controlling the ectivene-ss of the motive source upon the. sealin'gflmechu-n'ism, exhausting means for decreasing the pressure in the chamber, a movable member responsive to pressure changes in the chamber and operable to close the chamber from {he exhausting means, and an operative connection between said member and the clutch.

11.. In a. vacuum sealing machine. in (tour birratiou, a chamber, means for scaling: :1 package in said chamber, means for exhausting the chamber, a motive source [or operating the sealing means, a device operativel res onsive to pressure changes in the chamber or rendering the motive suurrc efiective upon the sealing means, and mean: for operating said device to rent the ch:unber.

12. In a package closing machine, in combination, a chamber, means for drawing :1 vacuum in said chamber, operating: moi-buuism associated with the chamber. 1: clutch control member associated with said upcrnling mechanism, and a member I'OSDUEisiYv In ressure changes in the chamber For J|iLi':iimg the clutch control member, said operating mechanism including means offer-tire (in the clutch control member to fi urztic the pressure responsive member to win llw chamber.

13. In an automatic sealing machine. the combination of a sealing; chamber. :1 conduit in which n suitable vacuum is adapted in I maintained, said conduit being operably connected with said scaling chamber. :1 con tinuously rotating drive shaft scal ng mechanism in the scaling;- rlnunbcr. and means comprising a derive responsive in pressure in the sealing chamber for arrow plisbing the connection of said (Ulllinllmlslt rotating drive shaft with the seulin; mechanism, said device being operable to vent thisealing chamber to atmosphere.

HARRY E. TOWNSEND.

Iii) 

